cosmopolitan/libc/time/xiso8601.c

82 lines
3.4 KiB
C

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 Justine Alexandra Roberts Tunney │
│ │
│ This program is free software; you can redistribute it and/or modify │
│ it under the terms of the GNU General Public License as published by │
│ the Free Software Foundation; version 2 of the License. │
│ │
│ This program is distributed in the hope that it will be useful, but │
│ WITHOUT ANY WARRANTY; without even the implied warranty of │
│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU │
│ General Public License for more details. │
│ │
│ You should have received a copy of the GNU General Public License │
│ along with this program; if not, write to the Free Software │
│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA │
│ 02110-1301 USA │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/calls/struct/timespec.h"
#include "libc/calls/struct/timeval.h"
#include "libc/dce.h"
#include "libc/errno.h"
#include "libc/mem/mem.h"
#include "libc/sysv/consts/clock.h"
#include "libc/time/struct/tm.h"
#include "libc/time/time.h"
#include "libc/x/x.h"
STATIC_YOINK("stoa");
STATIC_YOINK("ntoa");
/**
* @fileoverview Timestamps in One True Format w/o toil.
*/
static char *xiso8601$impl(struct timespec *opt_ts, int sswidth) {
char *p;
struct tm tm;
struct timespec ts;
int64_t sec, subsec;
char timebuf[64], zonebuf[8];
if (opt_ts) {
sec = opt_ts->tv_sec;
subsec = opt_ts->tv_nsec;
} else {
errno = 0;
clock_gettime(CLOCK_REALTIME, &ts);
sec = ts.tv_sec;
subsec = ts.tv_nsec;
sswidth = 9;
if (errno == ENOSYS) {
subsec /= 1000;
sswidth = 6;
}
}
if (IsWindows() && sswidth == 9) {
subsec /= 100;
sswidth = 7; /* windows nt uses hectonanoseconds */
}
localtime_r(&sec, &tm);
strftime(timebuf, sizeof(timebuf), "%Y-%m-%dT%H:%M:%S", &tm);
strftime(zonebuf, sizeof(zonebuf), "%z", &tm);
(asprintf)(&p, "%s.%0*ld%s", timebuf, sswidth, subsec, zonebuf);
return p;
}
/**
* Returns allocated string representation of nanosecond timestamp.
*/
char *xiso8601ts(struct timespec *opt_ts) {
return xiso8601$impl(opt_ts, 9);
}
/**
* Returns allocated string representation of microsecond timestamp.
*/
char *xiso8601tv(struct timeval *opt_tv) {
return xiso8601$impl(
opt_tv ? &(struct timespec){opt_tv->tv_sec, opt_tv->tv_usec} : NULL, 6);
}